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><H1
><A
NAME="SQL-ALTERFUNCTION"
></A
>ALTER FUNCTION</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN60492"
></A
><H2
>Name</H2
>ALTER FUNCTION&nbsp;--&nbsp;change the definition of a function</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN60497"
></A
><H2
>Synopsis</H2
><PRE
CLASS="SYNOPSIS"
>ALTER FUNCTION <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
> ( [ [ <TT
CLASS="REPLACEABLE"
><I
>argmode</I
></TT
> ] [ <TT
CLASS="REPLACEABLE"
><I
>argname</I
></TT
> ] <TT
CLASS="REPLACEABLE"
><I
>argtype</I
></TT
> [, ...] ] )
    <TT
CLASS="REPLACEABLE"
><I
>action</I
></TT
> [ ... ] [ RESTRICT ]
ALTER FUNCTION <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
> ( [ [ <TT
CLASS="REPLACEABLE"
><I
>argmode</I
></TT
> ] [ <TT
CLASS="REPLACEABLE"
><I
>argname</I
></TT
> ] <TT
CLASS="REPLACEABLE"
><I
>argtype</I
></TT
> [, ...] ] )
    RENAME TO <TT
CLASS="REPLACEABLE"
><I
>new_name</I
></TT
>
ALTER FUNCTION <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
> ( [ [ <TT
CLASS="REPLACEABLE"
><I
>argmode</I
></TT
> ] [ <TT
CLASS="REPLACEABLE"
><I
>argname</I
></TT
> ] <TT
CLASS="REPLACEABLE"
><I
>argtype</I
></TT
> [, ...] ] )
    OWNER TO <TT
CLASS="REPLACEABLE"
><I
>new_owner</I
></TT
>
ALTER FUNCTION <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
> ( [ [ <TT
CLASS="REPLACEABLE"
><I
>argmode</I
></TT
> ] [ <TT
CLASS="REPLACEABLE"
><I
>argname</I
></TT
> ] <TT
CLASS="REPLACEABLE"
><I
>argtype</I
></TT
> [, ...] ] )
    SET SCHEMA <TT
CLASS="REPLACEABLE"
><I
>new_schema</I
></TT
>

<SPAN
CLASS="phrase"
><SPAN
CLASS="PHRASE"
>where <TT
CLASS="REPLACEABLE"
><I
>action</I
></TT
> is one of:</SPAN
></SPAN
>

    CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT
    IMMUTABLE | STABLE | VOLATILE
    [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER
    COST <TT
CLASS="REPLACEABLE"
><I
>execution_cost</I
></TT
>
    ROWS <TT
CLASS="REPLACEABLE"
><I
>result_rows</I
></TT
>
    SET <TT
CLASS="REPLACEABLE"
><I
>configuration_parameter</I
></TT
> { TO | = } { <TT
CLASS="REPLACEABLE"
><I
>value</I
></TT
> | DEFAULT }
    SET <TT
CLASS="REPLACEABLE"
><I
>configuration_parameter</I
></TT
> FROM CURRENT
    RESET <TT
CLASS="REPLACEABLE"
><I
>configuration_parameter</I
></TT
>
    RESET ALL</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN60527"
></A
><H2
>Description</H2
><P
>   <TT
CLASS="COMMAND"
>ALTER FUNCTION</TT
> changes the definition of a
   function.
  </P
><P
>   You must own the function to use <TT
CLASS="COMMAND"
>ALTER FUNCTION</TT
>.
   To change a function's schema, you must also have <TT
CLASS="LITERAL"
>CREATE</TT
>
   privilege on the new schema.
   To alter the owner, you must also be a direct or indirect member of the new
   owning role, and that role must have <TT
CLASS="LITERAL"
>CREATE</TT
> privilege on
   the function's schema.  (These restrictions enforce that altering the owner
   doesn't do anything you couldn't do by dropping and recreating the function.
   However, a superuser can alter ownership of any function anyway.)
  </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN60535"
></A
><H2
>Parameters</H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
></DT
><DD
><P
>      The name (optionally schema-qualified) of an existing function.
     </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>argmode</I
></TT
></DT
><DD
><P
>      The mode of an argument: <TT
CLASS="LITERAL"
>IN</TT
>, <TT
CLASS="LITERAL"
>OUT</TT
>,
      <TT
CLASS="LITERAL"
>INOUT</TT
>, or <TT
CLASS="LITERAL"
>VARIADIC</TT
>.
      If omitted, the default is <TT
CLASS="LITERAL"
>IN</TT
>.
      Note that <TT
CLASS="COMMAND"
>ALTER FUNCTION</TT
> does not actually pay
      any attention to <TT
CLASS="LITERAL"
>OUT</TT
> arguments, since only the input
      arguments are needed to determine the function's identity.
      So it is sufficient to list the <TT
CLASS="LITERAL"
>IN</TT
>, <TT
CLASS="LITERAL"
>INOUT</TT
>,
      and <TT
CLASS="LITERAL"
>VARIADIC</TT
> arguments.
     </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>argname</I
></TT
></DT
><DD
><P
>      The name of an argument.
      Note that <TT
CLASS="COMMAND"
>ALTER FUNCTION</TT
> does not actually pay
      any attention to argument names, since only the argument data
      types are needed to determine the function's identity.
     </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>argtype</I
></TT
></DT
><DD
><P
>      The data type(s) of the function's arguments (optionally
      schema-qualified), if any.
     </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>new_name</I
></TT
></DT
><DD
><P
>      The new name of the function.
     </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>new_owner</I
></TT
></DT
><DD
><P
>      The new owner of the function.  Note that if the function is
      marked <TT
CLASS="LITERAL"
>SECURITY DEFINER</TT
>, it will subsequently
      execute as the new owner.
     </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>new_schema</I
></TT
></DT
><DD
><P
>      The new schema for the function.
     </P
></DD
><DT
><TT
CLASS="LITERAL"
>CALLED ON NULL INPUT</TT
><BR><TT
CLASS="LITERAL"
>RETURNS NULL ON NULL INPUT</TT
><BR><TT
CLASS="LITERAL"
>STRICT</TT
></DT
><DD
><P
><TT
CLASS="LITERAL"
>CALLED ON NULL INPUT</TT
> changes the function so
       that it will be invoked when some or all of its arguments are
       null. <TT
CLASS="LITERAL"
>RETURNS NULL ON NULL INPUT</TT
> or
       <TT
CLASS="LITERAL"
>STRICT</TT
> changes the function so that it is not
       invoked if any of its arguments are null; instead, a null result
       is assumed automatically.  See <A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
>
       for more information.
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>IMMUTABLE</TT
><BR><TT
CLASS="LITERAL"
>STABLE</TT
><BR><TT
CLASS="LITERAL"
>VOLATILE</TT
></DT
><DD
><P
>       Change the volatility of the function to the specified setting.
       See <A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
> for details.
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>[<SPAN
CLASS="OPTIONAL"
> EXTERNAL </SPAN
>] SECURITY INVOKER</TT
><BR><TT
CLASS="LITERAL"
>[<SPAN
CLASS="OPTIONAL"
> EXTERNAL </SPAN
>] SECURITY DEFINER</TT
></DT
><DD
><P
>      Change whether the function is a security definer or not. The
      key word <TT
CLASS="LITERAL"
>EXTERNAL</TT
> is ignored for SQL
      conformance. See <A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
> for more information about
      this capability.
     </P
></DD
><DT
><TT
CLASS="LITERAL"
>COST</TT
> <TT
CLASS="REPLACEABLE"
><I
>execution_cost</I
></TT
></DT
><DD
><P
>       Change the estimated execution cost of the function.
       See <A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
> for more information.
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>ROWS</TT
> <TT
CLASS="REPLACEABLE"
><I
>result_rows</I
></TT
></DT
><DD
><P
>       Change the estimated number of rows returned by a set-returning
       function.  See <A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
> for more information.
      </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>configuration_parameter</I
></TT
><BR><TT
CLASS="REPLACEABLE"
><I
>value</I
></TT
></DT
><DD
><P
>        Add or change the assignment to be made to a configuration parameter
        when the function is called.  If
        <TT
CLASS="REPLACEABLE"
><I
>value</I
></TT
> is <TT
CLASS="LITERAL"
>DEFAULT</TT
>
        or, equivalently, <TT
CLASS="LITERAL"
>RESET</TT
> is used, the function-local
        setting is removed, so that the function executes with the value
        present in its environment.  Use <TT
CLASS="LITERAL"
>RESET
        ALL</TT
> to clear all function-local settings.
        <TT
CLASS="LITERAL"
>SET FROM CURRENT</TT
> saves the session's current value of
        the parameter as the value to be applied when the function is entered.
       </P
><P
>        See <A
HREF="sql-set.html"
>SET</A
> and
        <A
HREF="runtime-config.html"
>Chapter 18</A
>
        for more information about allowed parameter names and values.
       </P
></DD
><DT
><TT
CLASS="LITERAL"
>RESTRICT</TT
></DT
><DD
><P
>      Ignored for conformance with the SQL standard.
     </P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN60653"
></A
><H2
>Examples</H2
><P
>   To rename the function <TT
CLASS="LITERAL"
>sqrt</TT
> for type
   <TT
CLASS="TYPE"
>integer</TT
> to <TT
CLASS="LITERAL"
>square_root</TT
>:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER FUNCTION sqrt(integer) RENAME TO square_root;</PRE
><P>
  </P
><P
>   To change the owner of the function <TT
CLASS="LITERAL"
>sqrt</TT
> for type
   <TT
CLASS="TYPE"
>integer</TT
> to <TT
CLASS="LITERAL"
>joe</TT
>:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER FUNCTION sqrt(integer) OWNER TO joe;</PRE
><P>
  </P
><P
>   To change the schema of the function <TT
CLASS="LITERAL"
>sqrt</TT
> for type
   <TT
CLASS="TYPE"
>integer</TT
> to <TT
CLASS="LITERAL"
>maths</TT
>:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER FUNCTION sqrt(integer) SET SCHEMA maths;</PRE
><P>
  </P
><P
>   To adjust the search path that is automatically set for a function:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER FUNCTION check_password(text) SET search_path = admin, pg_temp;</PRE
><P>
  </P
><P
>   To disable automatic setting of <TT
CLASS="VARNAME"
>search_path</TT
> for a function:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER FUNCTION check_password(text) RESET search_path;</PRE
><P>
   The function will now execute with whatever search path is used by its
   caller.
  </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN60675"
></A
><H2
>Compatibility</H2
><P
>   This statement is partially compatible with the <TT
CLASS="COMMAND"
>ALTER
   FUNCTION</TT
> statement in the SQL standard. The standard allows more
   properties of a function to be modified, but does not provide the
   ability to rename a function, make a function a security definer,
   attach configuration parameter values to a function,
   or change the owner, schema, or volatility of a function. The standard also
   requires the <TT
CLASS="LITERAL"
>RESTRICT</TT
> key word, which is optional in
   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>.
  </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN60681"
></A
><H2
>See Also</H2
><A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
>, <A
HREF="sql-dropfunction.html"
>DROP FUNCTION</A
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